An announcement by the state National Election Committee showed that the Cambodian People's Party had swept the polls, ensuring that Hun Sen, who has held power for 33 years, will receive another five-year term.

Both the legitimacy and the results of the polls had already been challenged by Hun Sen's opponents, who say the July 29 vote was not fair because the Cambodia National Rescue Party, the only credible opposition force, was disbanded last year by court order after a complaint by the government.

Critics also were skeptical about the July 29 vote itself. The former leaders of the opposition CNRP called for a voter boycott of the election, but the official turnout was a high 83 percent. Hun Sen's party also won more than two-thirds of the vote in every province.

Nineteen parties had competed against Hun Sen's CPP, but almost all were vanity vehicles or groups serving as window-dressing to give the illusion of democratic choice.

The new parliament is to convene on Sept. 5, and the next government is to be installed on Sept. 6.

"This result shows that our compatriots fully believed in the right leadership of the Cambodian People's Party which is led by Prime Minister Hun Sen," Hun Sen said on his Facebook page after the announcement of the official results, adding that voting for his party meant voting for peace and development for the entire country.

He called the July 29 election free and fair and said it was conducted according to the principle of democracy.

In a speech earlier Wednesday to thousands of garment workers, Hun Sen said he wanted to hold a meeting with the leaders of the 19 other parties that contested the election, and was considering offering them positions as government advisers or senior posts in various ministries.

Sam Rainsy, the self-exiled founder of the opposition CNRP and Hun Sen's chief political nemesis, said the official voting results were fraudulent.

On his Facebook page, he said Wednesday that the vote totals were inflated by 2 million -- purportedly cast in the names of people who did not go to the polls -- and that all those votes were counted as being for the ruling CPP.

He said the National Election Committee "was able to play all sorts of tricks because, after the forceful dissolution of the CNRP, the election body was placed under the absolute control of the CPP. There were no independent and credible observers and no CNRP representatives to monitor this election."

Several established poll-watching groups -- as well as national contingents from the United States and the European Union -- declined to take part because they felt the polls were not legitimate. One of the bigger Cambodian groups participating in poll-watching was led by one of Hun Sen's sons.

Hun Sen's party was alarmed by the results of the last general election in 2013, when the race was close enough for the opposition to claim that it would have won had it not been for manipulation of the voter registration process.

Cambodia's Supreme Court last November ordered the opposition CNRP dissolved on the pretext that it had conspired with the United States to overthrow the government. It banned its leaders from holding office for five years and expelled its members from the elective positions they held. Sam Rainy already was in exile and the other party founder was in jail awaiting trial on the treason charge.

Hun Sen's government also silenced critical voices in the media. Over the past year, about 30 radio stations shut down and two English-language newspapers that provided serious reporting were gutted, one forced to close and the other put under ownership friendly to the government.

After initial election results were earlier announced, the United States said it regretted the "flawed elections" and would consider its response, including expanding visa restrictions that were announced in December.

A statement from the White House press secretary's office said the U.S. was disappointed in the government's decision to disenfranchise voters, citing the exclusion of the principal opposition party, the jailing and banning of its officials, and threats to punish nonvoters.